mach-snapdragon: implement capsule update support

Qualcomm boards flash U-Boot to the boot partition, implement support
for determining which slot U-Boot is running from and finding the
correct boot partition for that slot and configuring the appropriate DFU
string.

For now this only supports boards with SCSI/UFS storage where U-Boot is
flashed to the boot partition, and only U-Boot itself is updated. In the
future we may also support updating additional firmware components (tz,
hyp, xbl) as well as having U-Boot installed to other partitions (e.g.
as a first-stage bootloader).

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
5 files changed